The present invention relates to a cooling system for an engine powered non-rail off-road work vehicle such as an agricultural tractor.
Current tractor cooling systems have components, such as a fan and a water pump which are mechanically driven by the engine. The mechanical drive limits the location of such components to on or near a rotation axis and at the front of the engine. A large amount of mechanical engine power is consumed in driving the fan. This degrades vehicle performance and fuel economy and results in high noise levels. Such tractor cooling systems also take up a lot of space in areas that interfere with the operator's view in the forward direction. Such cooling systems may also blow heated air back toward the cab, thus heating the cab substantially, and increasing the heat load on the cab cooling and air conditioning system. In certain conditions, such as a tail wind, the hot air blown by such cooling systems may, instead of exiting the region of the tractor, be recirculated or drawn back into the radiator. Cooling system capacity must be increased to handle this effect. A more efficient cooling system which avoids hot air recirculation is desired.
A diesel-electric railway locomotive design is known wherein the engine is located behind the locomotive cab and a cooling unit is spaced apart from and behind the engine. The cooling unit includes a number of radiators and electric motor-driven 2-speed fans. However, in most off-road vehicles, such as agricultural tractors, there is insufficient fore-and-aft room for such an arrangement of components, and there has not previously been sufficient electrical power capacity to power electric motor-driven cooling fans.